text: /*-
   * Copyright (c) 2001 Charles Mott <cm@linktel.net>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * $FreeBSD: releng/9.3/sys/netinet/libalias/alias_local.h 223437 2011-06-22 20:00:27Z ae $
   */
  
  /*
   * Alias_local.h contains the function prototypes for alias.c,
   * alias_db.c, alias_util.c and alias_ftp.c, alias_irc.c (as well
   * as any future add-ons).  It also includes macros, globals and
   * struct definitions shared by more than one alias*.c file.
   *
   * This include file is intended to be used only within the aliasing
   * software.  Outside world interfaces are defined in alias.h
   *
   * This software is placed into the public domain with no restrictions
   * on its distribution.
   *
   * Initial version:  August, 1996  (cjm)
   *
   * <updated several times by original author and Eivind Eklund>
   */
  
  #ifndef _ALIAS_LOCAL_H_
  #define	_ALIAS_LOCAL_H_
  
  #include <sys/types.h>
  #include <sys/sysctl.h>
  
  #ifdef _KERNEL
  #include <sys/malloc.h>
  #include <sys/param.h>
  #include <sys/lock.h>
  #include <sys/mutex.h>
  
  /* XXX: LibAliasSetTarget() uses this constant. */
  #define	INADDR_NONE	0xffffffff
  
  #include <netinet/libalias/alias_sctp.h>
  #else
  #include "alias_sctp.h"
  #endif
  
  /* Sizes of input and output link tables */
  #define LINK_TABLE_OUT_SIZE        4001
  #define LINK_TABLE_IN_SIZE         4001
  
  #define	GET_ALIAS_PORT		-1
  #define	GET_ALIAS_ID		GET_ALIAS_PORT
  
  struct proxy_entry;
  
  struct libalias {
  	LIST_ENTRY(libalias) instancelist;
  
  	int		packetAliasMode;	/* Mode flags                      */
  	/* - documented in alias.h  */
  
  	struct in_addr	aliasAddress;	/* Address written onto source     */
  	/* field of IP packet.           */
  
  	struct in_addr	targetAddress;	/* IP address incoming packets     */
  	/* are sent to if no aliasing    */
  	/* link already exists           */
  
  	struct in_addr	nullAddress;	/* Used as a dummy parameter for   */
  	/* some function calls           */
  
  			LIST_HEAD     (, alias_link) linkTableOut[LINK_TABLE_OUT_SIZE];
  	/* Lookup table of pointers to     */
  	/* chains of link records. Each  */
  
  			LIST_HEAD     (, alias_link) linkTableIn[LINK_TABLE_IN_SIZE];
  	/* link record is doubly indexed */
  	/* into input and output lookup  */
  	/* tables.                       */
  
  	/* Link statistics                 */
  	int		icmpLinkCount;
  	int		udpLinkCount;
  	int		tcpLinkCount;
  	int		pptpLinkCount;
  	int		protoLinkCount;
  	int		fragmentIdLinkCount;
  	int		fragmentPtrLinkCount;
  	int		sockCount;
  
  	int		cleanupIndex;	/* Index to chain of link table    */
  	/* being inspected for old links   */
  
  	int		timeStamp;	/* System time in seconds for      */
  	/* current packet                  */
  
  	int		lastCleanupTime;	/* Last time
  						 * IncrementalCleanup()  */
  	/* was called                      */
  
  	int		deleteAllLinks;	/* If equal to zero, DeleteLink()  */
  	/* will not remove permanent links */
  	
  	/* log descriptor        */ 
  #ifdef  _KERNEL
  	char           *logDesc;        
  #else 
  	FILE           *logDesc;	
  #endif
  	/* statistics monitoring */
  
  	int		newDefaultLink;	/* Indicates if a new aliasing     */
  	/* link has been created after a   */
  	/* call to PacketAliasIn/Out().    */
  
  #ifndef NO_FW_PUNCH
  	int		fireWallFD;	/* File descriptor to be able to   */
  	/* control firewall.  Opened by    */
  	/* PacketAliasSetMode on first     */
  	/* setting the PKT_ALIAS_PUNCH_FW  */
  	/* flag.                           */
  	int		fireWallBaseNum;	/* The first firewall entry
  						 * free for our use */
  	int		fireWallNumNums;	/* How many entries can we
  						 * use? */
  	int		fireWallActiveNum;	/* Which entry did we last
  						 * use? */
  	char           *fireWallField;	/* bool array for entries */
  #endif
  
  	unsigned int	skinnyPort;	/* TCP port used by the Skinny     */
  	/* protocol.                       */
  
  	struct proxy_entry *proxyList;
  
  	struct in_addr	true_addr;	/* in network byte order. */
  	u_short		true_port;	/* in host byte order. */
  
  	/*
  	 * sctp code support
  	 */
  
  	/* counts associations that have progressed to UP and not yet removed */
  	int		sctpLinkCount;
  #ifdef  _KERNEL
  	/* timing queue for keeping track of association timeouts */
  	struct sctp_nat_timer sctpNatTimer;
  	
  	/* size of hash table used in this instance */
  	u_int sctpNatTableSize;
  	
  /* 
   * local look up table sorted by l_vtag/l_port 
   */
  	LIST_HEAD(sctpNatTableL, sctp_nat_assoc) *sctpTableLocal;
  /* 
   * global look up table sorted by g_vtag/g_port 
   */
  	LIST_HEAD(sctpNatTableG, sctp_nat_assoc) *sctpTableGlobal;
  	
  	/* 
  	 * avoid races in libalias: every public function has to use it.
  	 */
  	struct mtx mutex;
  #endif
  };
  
  /* Macros */
  
  #ifdef _KERNEL
  #define LIBALIAS_LOCK_INIT(l) \
          mtx_init(&l->mutex, "per-instance libalias mutex", NULL, MTX_DEF)
  #define LIBALIAS_LOCK_ASSERT(l) mtx_assert(&l->mutex, MA_OWNED)
  #define LIBALIAS_LOCK(l) mtx_lock(&l->mutex)
  #define LIBALIAS_UNLOCK(l) mtx_unlock(&l->mutex)
  #define LIBALIAS_LOCK_DESTROY(l)	mtx_destroy(&l->mutex)
  #else
  #define LIBALIAS_LOCK_INIT(l)
  #define LIBALIAS_LOCK_ASSERT(l)
  #define LIBALIAS_LOCK(l)
  #define LIBALIAS_UNLOCK(l)
  #define LIBALIAS_LOCK_DESTROY(l)
  #endif
  
  /*
   * The following macro is used to update an
   * internet checksum.  "delta" is a 32-bit
   * accumulation of all the changes to the
   * checksum (adding in new 16-bit words and
   * subtracting out old words), and "cksum"
   * is the checksum value to be updated.
   */
  #define	ADJUST_CHECKSUM(acc, cksum) \
  	do { \
  		acc += cksum; \
  		if (acc < 0) { \
  			acc = -acc; \
  			acc = (acc >> 16) + (acc & 0xffff); \
  			acc += acc >> 16; \
  			cksum = (u_short) ~acc; \
  		} else { \
  			acc = (acc >> 16) + (acc & 0xffff); \
  			acc += acc >> 16; \
  			cksum = (u_short) acc; \
  		} \
  	} while (0)
  
  
  /* Prototypes */
  
  /*
   * SctpFunction prototypes
   * 
   */
  void AliasSctpInit(struct libalias *la);
  void AliasSctpTerm(struct libalias *la);
  int SctpAlias(struct libalias *la, struct ip *ip, int direction);
  
  /*
   * We do not calculate TCP checksums when libalias is a kernel
   * module, since it has no idea about checksum offloading.
   * If TCP data has changed, then we just set checksum to zero,
   * and caller must recalculate it himself.
   * In case if libalias will edit UDP data, the same approach
   * should be used.
   */
  #ifndef _KERNEL
  u_short		IpChecksum(struct ip *_pip);
  u_short		TcpChecksum(struct ip *_pip);
  #endif
  void
  DifferentialChecksum(u_short * _cksum, void * _new, void * _old, int _n);
  
  /* Internal data access */
  struct alias_link *
  AddLink(struct libalias *la, struct in_addr src_addr, struct in_addr dst_addr,
      struct in_addr alias_addr, u_short src_port, u_short dst_port,
      int alias_param, int link_type);
  struct alias_link *
  FindIcmpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
      u_short _id_alias, int _create);
  struct alias_link *
  FindIcmpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
      u_short _id, int _create);
  struct alias_link *
  FindFragmentIn1(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
      u_short _ip_id);
  struct alias_link *
  FindFragmentIn2(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
      u_short _ip_id);
  struct alias_link *
  		AddFragmentPtrLink(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
  struct alias_link *
  		FindFragmentPtr(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
  struct alias_link *
  FindProtoIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
      u_char _proto);
  struct alias_link *
  FindProtoOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
      u_char _proto);
  struct alias_link *
  FindUdpTcpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
      u_short _dst_port, u_short _alias_port, u_char _proto, int _create);
  struct alias_link *
  FindUdpTcpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
      u_short _src_port, u_short _dst_port, u_char _proto, int _create);
  struct alias_link *
  AddPptp(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
      struct in_addr _alias_addr, u_int16_t _src_call_id);
  struct alias_link *
  FindPptpOutByCallId(struct libalias *la, struct in_addr _src_addr,
      struct in_addr _dst_addr, u_int16_t _src_call_id);
  struct alias_link *
  FindPptpInByCallId(struct libalias *la, struct in_addr _dst_addr,
      struct in_addr _alias_addr, u_int16_t _dst_call_id);
  struct alias_link *
  FindPptpOutByPeerCallId(struct libalias *la, struct in_addr _src_addr,
      struct in_addr _dst_addr, u_int16_t _dst_call_id);
  struct alias_link *
  FindPptpInByPeerCallId(struct libalias *la, struct in_addr _dst_addr,
      struct in_addr _alias_addr, u_int16_t _alias_call_id);
  struct alias_link *
  FindRtspOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
      u_short _src_port, u_short _alias_port, u_char _proto);
  struct in_addr
  		FindOriginalAddress(struct libalias *la, struct in_addr _alias_addr);
  struct in_addr
  		FindAliasAddress(struct libalias *la, struct in_addr _original_addr);
  struct in_addr 
  FindSctpRedirectAddress(struct libalias *la,  struct sctp_nat_msg *sm);
  
  /* External data access/modification */
  int
  FindNewPortGroup(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
      u_short _src_port, u_short _dst_port, u_short _port_count,
      u_char _proto, u_char _align);
  void		GetFragmentAddr(struct alias_link *_lnk, struct in_addr *_src_addr);
  void		SetFragmentAddr(struct alias_link *_lnk, struct in_addr _src_addr);
  void		GetFragmentPtr(struct alias_link *_lnk, char **_fptr);
  void		SetFragmentPtr(struct alias_link *_lnk, char *fptr);
  void		SetStateIn(struct alias_link *_lnk, int _state);
  void		SetStateOut(struct alias_link *_lnk, int _state);
  int		GetStateIn (struct alias_link *_lnk);
  int		GetStateOut(struct alias_link *_lnk);
  struct in_addr
  		GetOriginalAddress(struct alias_link *_lnk);
  struct in_addr
  		GetDestAddress(struct alias_link *_lnk);
  struct in_addr
  		GetAliasAddress(struct alias_link *_lnk);
  struct in_addr
  		GetDefaultAliasAddress(struct libalias *la);
  void		SetDefaultAliasAddress(struct libalias *la, struct in_addr _alias_addr);
  u_short		GetOriginalPort(struct alias_link *_lnk);
  u_short		GetAliasPort(struct alias_link *_lnk);
  struct in_addr
  		GetProxyAddress(struct alias_link *_lnk);
  void		SetProxyAddress(struct alias_link *_lnk, struct in_addr _addr);
  u_short		GetProxyPort(struct alias_link *_lnk);
  void		SetProxyPort(struct alias_link *_lnk, u_short _port);
  void		SetAckModified(struct alias_link *_lnk);
  int		GetAckModified(struct alias_link *_lnk);
  int		GetDeltaAckIn(u_long, struct alias_link *_lnk);
  int             GetDeltaSeqOut(u_long, struct alias_link *lnk);
  void            AddSeq(struct alias_link *lnk, int delta, u_int ip_hl, 
  		    u_short ip_len, u_long th_seq, u_int th_off);
  void		SetExpire (struct alias_link *_lnk, int _expire);
  void		ClearCheckNewLink(struct libalias *la);
  void		SetProtocolFlags(struct alias_link *_lnk, int _pflags);
  int		GetProtocolFlags(struct alias_link *_lnk);
  void		SetDestCallId(struct alias_link *_lnk, u_int16_t _cid);
  
  #ifndef NO_FW_PUNCH
  void		PunchFWHole(struct alias_link *_lnk);
  
  #endif
  
  /* Housekeeping function */
  void		HouseKeeping(struct libalias *);
  
  /* Tcp specfic routines */
  /* lint -save -library Suppress flexelint warnings */
  
  /* Transparent proxy routines */
  int
  ProxyCheck(struct libalias *la, struct in_addr *proxy_server_addr,
      u_short * proxy_server_port, struct in_addr src_addr, 
      struct in_addr dst_addr, u_short dst_port, u_char ip_p);
  void
  ProxyModify(struct libalias *la, struct alias_link *_lnk, struct ip *_pip,
      int _maxpacketsize, int _proxy_type);
  
  enum alias_tcp_state {
  	ALIAS_TCP_STATE_NOT_CONNECTED,
  	ALIAS_TCP_STATE_CONNECTED,
  	ALIAS_TCP_STATE_DISCONNECTED
  };
  
  #if defined(_NETINET_IP_H_)
  static __inline void *
  ip_next(struct ip *iphdr)
  {
  	char *p = (char *)iphdr;
  	return (&p[iphdr->ip_hl * 4]);
  }
  #endif
  
  #if defined(_NETINET_TCP_H_)
  static __inline void *
  tcp_next(struct tcphdr *tcphdr)
  {
  	char *p = (char *)tcphdr;
  	return (&p[tcphdr->th_off * 4]);
  }
  #endif
  
  #if defined(_NETINET_UDP_H_)
  static __inline void *
  udp_next(struct udphdr *udphdr)
  {
  	return ((void *)(udphdr + 1));
  }
  #endif
  
  #endif				/* !_ALIAS_LOCAL_H_ */
  